El Niño = the boy, La Niña = the girl. You can tell from the ending and the first word.
Number of moles= mass/ molar mass
Or n=m/MM
n = number of moles
m = mass
MM = molar mass
1) n CuO = 2.4g / 79.54g/mol = 0.03 mol CuO
2) n Cu(NO3)2.xH2O = 7.26 g / 205.6 = 0.035 moles of Cu(NO3)2.xH2O
3) 205.6 g
Cu = 63.5 g
N = 14g
O =16g
H= 1 g
63.5+ (14+(16*3))*2+1*2+16 =205.6 g
4) yes is 188g
5) I don’t know, I assume was 1
